A treatise of artificial magnets ; in which is shewn an easy and expeditious method of making them, superior to the best natural ones, and also, a way of improving the natural ones, and of changing or converting their poles : Directions are likewise given for making the mariner's needles. In the best form, and for touching them most advantageously, &c / by J. Michell.

  • Michell, John, 1724?-1793.
Date:
1750
Catalogue details

Licence: Public Domain Mark

Credit: A treatise of artificial magnets ; in which is shewn an easy and expeditious method of making them, superior to the best natural ones, and also, a way of improving the natural ones, and of changing or converting their poles : Directions are likewise given for making the mariner's needles. In the best form, and for touching them most advantageously, &c / by J. Michell. Source: Wellcome Collection.

    27/86 (page 25)
    till it proves better: one of the beft fix-inch bars, I ever made, was one of the worft, till it had been hardened fix or feven different times. / As the common bliflered Steel is as good for our purpofe as any, a dozen fuch bars, as thofe defcribed above, together with a proper box to put them in, may be afforded for a very fmall fum ; and fuch a Set is capable of touching a much larger Needle, than the beft Natural Magnet yet difcovered. In order to preferve thefe bars, it will be proper to have a box contrived, that fhall have two pieces of Iron, of about an inch long each, (which will be about equal to the thicknefs of half a dozen of the Magnetical bars,) fixed upright overagainft each other at the diftance of fix inches from outfide to outfide. Thefe pieces of Iron may be about a quarter of an inch fquare, or fome- what more, and fhould be filed pretty fmooth on the fides: Againft thefe are to be placed, with their Edges towards them, the dozen Mag¬ netical bars, fix on one fide of them, and fix on the other ; the fix on one fide with their South, or North Poles one way, and thofe on the other fide with the fame Poles the contrary way.— And here it is to be obferved, that they muft neither be taken out, nor put in all, or too many on a fide at once 5 for if two only be D left. T - *